The performance of commercial initiators on thiol-ene polymerization has been investigated by utilizing the M062X/6-31++G(d,p) level of theory. The reactivity of initiators has been explained by the rate coefficients of addition (k_i), which is considered side reaction and hydrogen abstraction (k_HA) reactions. In this respect, radicals generated from azobisisobutyronitrile (AIBN) and 2,2-dimethoxy-2-phenylacetophenone (DMPA) have been modeled. In the case of AIBN and the propene-methyl thiol couple as reactants, it has been illustrated that side reaction is highly possible because the calculated rate coefficients k_i and k_HA are close to each other 1.02E+00 and 1.50E+02 l mol^–1 s^–1, respectively. In styrene, methyl methacrylate, and maleimide applications, the discrepancy between these reaction rates is relatively less. The high reactivity of DMPA has been explained by possessing high k_HA values of formed radicals. The hydrogen abstraction reaction is significantly faster than the addition reactions for generated radicals methyl (CH₃•) and benzoyl (C₆H₅CO•). For methyl methacrylate, side reaction is probable even in the application of DMPA since relatively fast addition reactions (the k_i for CH₃• and C₆H₅CO• radicals are 4.71E+04 and 3.42E+04 l mol^–1 s^–1 respectively.). Styrene and maleimide show a similar reactivity tendency with methyl methacrylate.

中文翻译：

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引发剂结构对硫醇-烯聚合的影响：DFT 研究

利用 M062X/6-31++G(d,p) 理论水平研究了商业引发剂对硫醇-烯聚合的性能。引发剂的反应性可以通过加成速率系数 ( k _i ) 来解释，这被认为是副反应和夺氢 ( k _HA ) 反应。在这方面，已对偶氮二异丁腈 (AIBN) 和 2,2-二甲氧基-2-苯基苯乙酮 (DMPA) 产生的自由基进行了建模。在 AIBN 和丙烯-甲基硫醇对作为反应物的情况下，由于计算的速率系数k _i和k _HA彼此接近 1.02E+00 和 1.50E+02 l ，因此表明副反应的可能性很高摩尔^–1 s ^–1，分别。在苯乙烯、甲基丙烯酸甲酯和马来酰亚胺应用中，这些反应速率之间的差异相对较小。DMPA 的高反应性可以通过具有高k _HA值来解释形成自由基。_{对于生成的自由基甲基 (CH 3} •) 和苯甲酰基 (C ₆ H ₅ CO• )，夺氢反应明显快于加成反应。对于甲基丙烯酸甲酯，即使在 DMPA 的应用中也可能发生副反应，因为加成反应相对较快（CH ₃ • 和 C ₆ H _5的k _iCO• 自由基分别为 4.71E+04 和 3.42E+04 l mol ^–1 s ^–1。）。苯乙烯和马来酰亚胺与甲基丙烯酸甲酯表现出相似的反应倾向。